TIMER

Online Alarm Clock

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Press “Lap” to record splits

How long to nap

Naps are not all the same thing. The length decides which sleep stages you pass through, and therefore what you feel like when the alarm goes off. The timer opens on a 20-minute nap; press any other length to load it. Stay under 20 minutes for a quick reset between tasks, take 60 to hold on to facts and figures, and take the full 90-minute cycle before a problem that needs a fresh angle.

10–20 min · alertness without grogginess
30 min · often leaves sleep inertia
60 min · includes slow-wave sleep
90 min · a full cycle including REM
Will it wake me if the tab is in the background?

The countdown keeps running and the alert plays when it finishes, but this is a page, not an operating-system alarm. It cannot wake the machine from sleep or override silent mode, so keep the tab open, the speakers on and the volume audible. For anything you truly cannot miss, use your phone's built-in alarm as well.

Why time a nap instead of just setting an alarm?

Because nap length is about cycles, not about a clock time. Waking at the end of a cycle is what leaves you clear-headed; being pulled out of deep sleep is what leaves you groggy. Press a length in the table above and start it the moment you lie down.

What is a coffee nap?

Drinking a coffee and then sleeping for about 20 minutes. Caffeine takes roughly that long to take effect, so the two arrive together — keep the nap short so you stay out of deep sleep.

Can I use it as a reminder for something in an hour?

Yes. Press the 60-minute chip and start it, or set 1 hour 0 minutes by hand. Give the timer a name and it shows in the browser tab, so you can see what the countdown is for without switching back to check.